Earthworm (Annelida: Clitellata) fauna of Chhattisgarh, India

: Present communication is the first study on earthworm fauna of Chhattisgarh in central India. A total of nine species belonging to seven genera and five families—Moniligastridae, Eudrilidae, Lumbricidae, Megascolecidae, and Octochaetidae—were collected from different parts of the state. Among the families, Megascolecidae is most dominant with maximum number of species; other families are represented by a single species in each. The earthworm fauna of the state is comprised of both native (5 species) and exotic peregrine (4 species). A brief description, distribution and identification key for the recorded species is provided. Further surveys are required, which could lead to finding of more species.


INTRODUCTION
In the year 2000, the state Chhattisgarh was curved out of Madhya Pradesh, comprising 1,35,192 km 2 , which constitutes about 4.11 percent of the country's land area. The state (GPS coordinates: 17.7833 0 N to 24.1000 0 N; 80.2500 0 E to 84.4000 0 E) is a part of the Deccan peninsula, a huge plateau between Eastern Ghats and Western Ghats biodiversity hotspots. It is part of the East Deccan physiographic zone and has three distinct agro-climatic zones: the Chhattisgarh plains, the northern hills of Chhattisgarh, and the Bastar Plateau. The Deccan Peninsula in central India is home to a large area of tropical dry deciduous and tropical moist deciduous forest, making it one of the most important ecosystems and biodiversity hotspots. Forests cover around 44% of the state's total area, and they are the source of some major river systems including the Mahanadi, Indravati, and Narmada.
The soil fauna plays a key role in functioning of soil ecosystems, such as recycling of organic matter, primary production and maintenance of soil structure (Verhoef 2004). Among soil invertebrates earthworm constitute the largest biomass in various ecosystems (Bhadauria & Saxena 2010;. Earthworms are known as ecosystem engineers, and their activities in the soil play an important role in maintaining a healthy and productive environment (Lavelle et al. 2006). Because earthworms are sensitive to habitat changes, they are considered as important bio-indicators and are widely used in environment assessment and pollution surveys (Howmiller & Beeton 1971;Julka 1988;Weber 2007;Martins et al. 2008;Ozdemir et al. 2011;Pelosi & Römbke 2016;Velki & Ecǐmović 2017). In addition, earthworms provide the essential conditions for transforming all sorts of decomposable organic wastes into recyclable micro-nutrients and organic fertilizers, and thus enhance the soil fertility (Dash & Senapati 1986;Reynolds & Eggen 1993).
Currently the earthworm fauna of India is represented by 453 species accredited to 10 families: Moniligastridae, Lumbricidae, Almidae, Rhinodrilidae, Acanthodrilidae, Eudrilidae, Ocnerodrilidae, Benhamiidae, Octochaetidae and Megascolecidae (Narayanan et al. 2020(Narayanan et al. , 2021Tiwari et al. 2021;Narayanan et al. 2022). India occupies about two percent of the total world surface area, but it harbours 10.5% of the globally known earthworm species (Julka et al. 2009). Endemism, both at the generic and species levels is extremely high, around 71% of genera and 85% of earthworm species are native to the country (Julka & Paliwal 2005). In India, the Western Ghats and western coastal plains are rich in earthworm fauna, accounting for about 58.4 percent of the country's total earthworm diversity (Goswami 2018;Narayanan et. al. 2020).
Although earthworms occur in all types of terrestrial habitats (except desert, and areas under snow & ice), but still several ecosystems are unexplored. As part of our study to assess the earthworm diversity of Deccan peninsula biogeographic zone, we sampled various habitats like agroecosystems, grassland, pasture, forest, and garbage sites. The listing of species is important for developing conservation strategies at a time when habitat shrinkage, climate change, and invasion poses a threat to sustaining biological diversity.

MATERIALS AND METHODS
Earthworms were collected from different habitats, viz., agroecosystems, grassland, pasture, forest, and garbage by digging and hand sorting method as proposed by Julka (1990). Collected specimens were washed in water and anesthetized in 70% alcohol and then after 24 hours were transferred to 5% formaldehyde solution for preservation. The anatomical observations were made by dorsal dissection under a binocular stereomicroscope (Leica EZ4). Specimens were identified following the monographs of Stephenson (1923); Gates (1945Gates ( , 1972; Julka (1988); Blakemore (2012), and Bantaowong et al. (2016). After identification, specimens were deposited and registered in General Non-Chordata (ZSI-GNC) section of Zoological Survey of India, Kolkata for future reference. A map is provided showing distribution of earthworm species in state Chhattisgarh ( Figure 1)
Climate change critically affects the biodiversity (Sintayehu 2018), and loss of an individual species can alter the structure and functions of an ecosystem and the services they provided to the society (Díaz et al. 2019;Weiskopf et al. 2020). Moreover, the invasive species also influence the existence of indigenous species (Migge-Kleian et al. 2006;Addison 2009;Bradley et al. 2019;Linders et al. 2019). Listing of species in the form of status assessment is important for developing future conservation strategies at a time when the habitat loss, climate change and invasion poses a major threat to existence of biological diversity which negatively reflect the functioning of ecosystems. Till date there is no report on earthworm species from Chhattisgarh.

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